Fluid pressure engine

ABSTRACT

This invention is an improved engine operated by gas under pressure having an improved valve guide, lubrication system, speed adjustment device, wrist pin, gas storage area, hollow crank shaft, and O-ring seal for the cylinder head. These improvements are positioned on a miniature engine capable of being used on tiny model airplanes, other power toys or the like.

United States Patent Brown, 4th

[ 1 Nov. 28, 1972 FLUID PRESSURE ENGINE [72] Inventor: William L. Brown, 4th, P. O. Box

77, Pine Grove Mills, Pa. 16868 22 Filed: Sept. 14,1970

21 Appl.No.: 72,030

FOREIGN PATENTS OR APPLICATIONS 1,171,409 10/1958 France ..91/410 Primary Examiner-Paul E. Maslousky Attorney-Thomas E. Sterling [57] ABSTRACT This invention is an improved engine operated by gas under pressure having an improved valve guide, lubrication system, speed adjustment device, wrist pin, gas storage area, hollow crank shaft, and O-ring seal for the cylinder head. These improvements are positioned on a miniature engine capable of being used on tiny model airplanes, other power toys or the like.

8Clains,4DrawingFigures PATENTEDNHV28 m 3.703.848

SHEET 1 OF 2' Fig. 1.

INVENTOR Wm. L. Brown 4 M A 7' TOR/V5 Y PATENTED HHY 28 I972 SHEEI 2 OF 2 A r i'ORNE Y FLUID PRESSURE ENGINE The engine which is the subject of this invention is similar to the device described in US. Pat. No. 2,588,478 Engine by William L. Brown, 3rd and William L. Brown, 4th, hereinafter referred to as the original engine. The engine of the present invention has been miniaturized to a much smaller size than that described in the above Patent and modifications made which improve the efficiency, ease of operation and performance of the original engine.

This invention relates to engines, and more particularly to engines which may be built in extremely small sizes to serve as power plants for model airplanes or the like.

It is the principal object of the present invention to provide an improved engine capable of being operated by gas under pressure, stored in liquefied or compressed form, and in which higher speeds and improved adjustment of speeds is obtained.

It is a further object of this invention to provide an engine having an improved cylindrical valve guide which will allow increased engine speed and power.

It is another object of this invention to provide an engine having a contoured valve guide with constriction which will allow the engine to operate at increased speeds and power.

It is another object of this invention to provide an engine with an improved means of speed adjustment which is operable while the engine is running.

It is yet another object of this invention to provide an engine with an improved chamber in the cylinder head.

It is still another object of this invention to provide an engine with an adjustable cylinder head which may be sealed by finger operation.

It is another object of this invention to provide an engine with an improved lubrication system.

It is another object of this invention to provide an engine with an improved wrist pin assembly.

It is another object of this invention to provide an engine with an improved hollow crank shaft assembly.

It is yet another object of this invention to provide an engine with an improved air breather system.

Other objects and advantageous features of this invention will become apparent from the specification and claims.

The principal improvements of the present invention are as follows: An improved admission valve has been added. The valve seat as was originally made in the original engine was simply a cylindrically shaped hole too small for the ball to go through. The ball therein was sealed against a conical bevel. This worked well for low speed settings, but when set for high speed the ball would fail to seat properly, because it was further away from the valve seat and experienced less force to return it. This caused irregular running and waste of fuel and power. The problem was solved by the cylindrical valve guide of the present invention and the modifications thereof.

The original engine was intended to be lubricated through the exhaust ports while the piston was at the top of its stroke. The early manufacturers of the engine found that the cover plate on the back of the crank case as lubrication was concerned. It was really a crank case breather, to relieve pressure. In the present device pressure cannot be built up because the end portion of the piston from the exhaust ports is slotted in several places thus providing crank case breathing. These slots perform an additional function in the lower portion of the cylinder. The end portion of the cylinder is flared or expanded so that it bears outwardly against the crank case when screwed therein. Thus a tight fit is obtained which may be adjusted by hand, eliminating the lock nut assembly on the previously patented engine. This improvement provides an opportunity to adjust the speed of the engine over a wide range. If desired, the adjustments can be made while the engine is running. The engine can be adjusted to suit the power requirements of a range of air craft sizes and types, and test flights or glides can be made under reduced power. The easily adjusted speed settings provide a means to synchronize the power plant of a multi engine ship. In

such a case all engines can be supplied from one source of fuel, hence they can be made to pull equally and to quit together when the fuel is gone.

The cylinder head has been redesigned to provide a much larger storage chamber, hence a much larger supply of gas under pressure which is ready for quick admission to the expansion chamber above the piston. Instead of a flat washer, which was present in the original engine, and which required a wrench, a new 0- ring is provided which may be assembled finger tight and hold full gas pressure. p

The construction of the wrist pin and wrist pin bearing has been improved from the original engine to provide a means for permanently locking the wrist pin from sliding out and contacting the cylinder wall. In this method the wrist pin is bent to bear against the internal portion of the piston thus locking it. This construction provides an efficient means to hold and drive the piston rod and wrist pin assembly when the piston is honed and lapped.

In addition the lubrication system of this engine has been improved over that of the original engine by the insertion of an absorbent material surrounding the shaft near the main bearing. This absorbent material permits retention of the lubricant and hence extends the time needed between engine lubrications.

FIG. 1 is a view partly in elevation and partly in vertical section showing a preferred embodiment of the improved engine in accordance, with the present inventron;

FIG. 2 is a vertical sectional view taken approximately on the line 22 of FIG. 1.

FIG. 3 is a vertical sectional view of the invention showing a modification of the valve assembly of FIG. 2.

FIG. 4 is a vertical sectional view of the invention showing another modification of the valve assembly of FIG. 2.

Referring to the drawings of the engine, the present invention preferably includes a crank case 10 preferably formed as a one piece die casting having one or more outstanding lugs 12 through which bolts 14 are adapted to extend for mounting the engine in position in the fuselage of a model airplane, or in any other desired location.

The crank case 10 preferably has a closure plate 16 at one side thereof which may be secured in position in any desired manner. The opposite side of the crank case preferably has an inner bearing 18 and an outer bearing 20 within which a crank shaft 22 is mounted for rotation. A lubrication space 24 is positioned between the crank case 10 and shaft 22. This space is packed with an oil absorbing material 25 such as wool, is saturated in oil and serves as a oil retaining reservoir to lubricate inner bearing 18 and outer bearing 20 during operation. The outside of the inner bearing 18 has grooves (not shown) to provide access for oil to reach the oil absorbing material. The crank shaft 22 is hollow and has an internally threaded end portion 26 adapted to receive a screw (not shown). The outer end of the crank shaft 22, beyond the outer bearing 20 has a clamping disc 27 connected thereto. A propeller or other driven member (not shown) may be clamped against clamping disc 27 by means of a screw (not shown) threaded upon threaded portion 26.

The inner end of the crank shaft 22 within the crank case 10 is provided with a circular crank disc 28 with a counter balance 29 thereon. The crank disc 28 serves to position the crank shaft 22 with respect to the inner bearing 18, and which has mounted therein a crank pin 30. The upper part of the crank case 10 has an outwardly extending boss or projection 32 provided with an internally threaded portion 34 for the reception of the lower externally threaded end 36 of a cylinder 38. The cylinder 38 is also preferably formed in one piece. The exterior of the cylinder 38 may be provided with fins 40 for heat absorption to prevent undue cooling of the engine upon expansion of the compressed gas, and to prevent condensation of gas or moisture upon expansion of gas during operation as well as to provide structural stiffening of the thin, lightweight cylinder wall.

The cylinder 38 is adjustable with respect to the crank case 10 by the engagement of threaded portion 36. The externally threaded end 36 of cylinder 38 has longitudenal slots 42 extending therethrough which connect with a plurality of exhaust ports 44 provided in communication with the interior of cylinder 38 and the atmosphere, and functioning as hereinafter explained. The threaded end 36 of cylinder 38 is expanded or flanged so that its diameter is greater than that of the diameter of cylinder 38. Hence when threaded portion 36 engages the internal threads 34 of projection 32, threaded end portion 36 bears outwardly against projection 32 creating a frictional engagement which holds cylinder 38 rigidly within projection 32. Thus no lock nut is required to secure cylinder 38 to projection 32. Cylinder 38 however may be turned by hand within the threaded portion 34 of projection 32 to move longitudenly therein.

The cylinder 38 is provided with an upwardly extending internally threaded portion 46 for the reception of an externally threaded cylinder head 48. An O-ring 50 of resilient material is interposed between cylinder head 48 and threaded portion 46 at the upper end of the cylinder 38 for the prevention of fluid leakage. By the utilization of O-ring 50, no wrench is required and a finger tight assembly is sufficient to hold the full gas pressure within cylinder head 48. The cylinder head 48 is provided with a compressed gas delivery tube 52 for the delivery of gas under pressure for the operation of the engine as hereinafter explained. The tube 52 is adapted to extend to the entrance of the internal portion of cylinder head 48.

Spaced downwardly from the upper end of the cylinder 48, a transverse wall 54 is provided which separates the space within the cylinder and below the cylinder head 48 into a working chamber 56. The wall 54 preferably has a central opening 58 therethrough, with a portion of conical shape to provide a valve seat 60 and to permit seating thereon of a spherical ball 62. Extending longitudenly upward and surrounding central opening 58 is a cylindrical valve guide 63 which extends within a fluid delivery chamber 65. The upper end portion of cylindrical valve guide 63 is flanged inwardly so as to form a constriction 61 small enough to contain spherical ball 62 within cylindrical valve guide 63. The ball 62 serves as an admission or inlet valve for the working chamber 56. Constriction 61 provides for ball retention plus additional returning force which permits good performance at high speeds.

Referring now to FIG. 3 there is shown an alternate constructionfor the valve seat assembly in which the cylindrical valve guide may be comprised of a hole in a thicker extending wall 64. Extending wall 64 may be comprised of plastic material or metal. In this construction gas delivery tube 52 extends within fluid delivery chamber 65 to a position directly above spherical ball 62 so as to prevent it from leaving cylindrical valve guide. In FIG. 3 there is no constriction 61 on the end portion of valve guide 63.

Likewise FIG. 4 indicates a cylindrical valve guide 67 of plastic or the like having a groove in the upper surface. No constriction 67 provides for ball retention plus additional retaining force which prevents good performance at high speeds. In FIG. 4 the gas delivery tube 52 extends only to the entrance of fluid delivery chamber 65.

Referring again to FIGS. 1 and 2 in the interior of cylinder 38 and in the working chamber 56 below the transverse wall 54, a piston 64 is provided for reciprocation and for controlling the exhaust ports 44. The piston 64 has a wrist pin 66 therein which is connected to a connecting rod 68 to the crank pin 30. An improved means of permanently locking wrist pin 66 has been utilized in this improved engine. The wrist pin is inserted through piston 64 and through connecting rod 68, then the end portion of wrist pin 66 is bent slightly so that it bears against the internal portion of piston 64 and cannot slide out of its entrance hole. Permanent locking of the wrist pin is thus obtained. This construction provides an eflicient means to hold and drive the piston rod 68 and wrist pin 66 assembly when the piston is honed and lapped.

On the upper face of the piston 64 a push rod or abutment 70 is provided for moving the ball 62 from its seat 60 within valve guide 63. When this is done fluid is emitted from the fluid delivery chamber 65 into the working chamber 56 as hereinafter explained. With the piston 64 in a position with the push rod 70 out of engagement with the ball 62 and with gaseous fluid under pressure supplied to the gas delivery tube 52 and through the gas delivery tube 52 to the chamber, the engine is ready to be operated. For operation, the shaft 22 is turned sharply by hand, such as a movement of the propeller if a propeller is employed and in the direction of rotation desired. The upward movement of the piston 64 causes the push rod 70 to engage the ball 62 and lift the same from its seat 60 within the valve guide 63 permitting fluid under pressure from the fluid delivery chamber 65 to pass into the working chamber 56 above the head of the piston 64. The valve guide 63 keeps the ball 62 constantly in a position to seat. With the valve guide 63 present, less force is necessary to return the ball 62 to the seat 60. As the piston 64 moves downwardly, the ball 62 by reason of its weight and the removal of push rod 70 is permitted to rest on the seat 60 and cut off further delivery of fluid to the working chamber 56. The fluid delivery chamber also aids the seating of the ball 62.

The fluid thus delivered in the working chamber 56 then expands and the piston 64 is moved downwardly by the expansion to a position to open the exhaust ports 44 and to permit the discharge of expanded gas to the atmosphere. As the piston 64 again moves upwardly, the push rod 70 again strikes the ball 62 and moves the same from its seat 60 to permit the delivery of gas under pressure from the gas delivery chamber 65 to the working chamber 56. The ball 62 again seats as before upon the downward movement of the piston 64. The operation of the engine will continue as long as the fluid is supplied through gas delivery tube 52. The gas delivery chamber 65 functions not only as a valve chamber but also as a storage chamber for pressure fluid and tends to eliminate fluctuations of pressure of the fluid admitted to the working chamber 56. In this improved engine, the size of the chamber has been greatly increased to provide a larger storage chamber having a much larger supply of gas under pressure.

Oiling of the engine may be readily affected through the exhaust ports 44. If it is desired to adjust the actuation of valve 62 to vary the speed, it is merely necessary to turn cylinder 38 with the fingers to screw it in or out of projection 32. The frictional force of threaded end 36 against projection 32 is sufficient to maintain position, as well as to eliminate the necessity of a lock washer. If the cylinder 38 is moved downwardly with respect to the crank case the length of the period of admission of gas is increased and the speed is increased and if the cylinder 38 is moved upwardly, the length of the period of admission of gas is decreased and the speed is decreased. The cylinder 38 is locked into the desired position of adjustment by the friction against projection 32 as previously described.

lclaim:

1. In an engine having a crank case with a crank rotably mounted therein, a cylinder, a partition member in said cylinder separating the interior of said cylinder into a valve chamber and a working chamber, means for delivering pressure fluid to said valve chamber, said partition member being provided with an opening therethrough having a valve seat, a valve member for engagement with said seat, a piston connected to said crank and reciprocable with a fixed stroke in said working chamber, said cylinder having exhaust ports at one and thereof controlled by the movement of said piston, an abutment carried by said piston movably into and through said opening to engage said valve and move it from its seat to admit pressure fluid to said working chamber for actuation said piston, and means for adjusting the extent of opening of said valve member co m rising an adjustable connection between said cylm er and said crank case, the

combination comprising:

A valve guide integrally attached to said partition member and extending therefrom, said valve member positioned within said valve guide; said valve guide having a constriction therein, said constriction adapted to retain said valve member within said cylindrical valve guide.

2. The combination as claimed in claim 1 in which said valve guide has a constriction therein, said constriction adapted to retain said valve member within said cylindrical valve guide.

3. The combination as claimed in claim 1 in which said adjustable connection between said cylinder and said crank case is comprised of in combination:

an expanded end portion of said cylinder, having gitudenal slots therein;

an adjustable engagement between said expanded end portion and said crank case permitting longitudenal shift of said cylinder to vary the extent of opening of said valve;

whereby said expanded portion of said cylinder bears against said crank case to create frictional rigidity allowing speed adjustment while said engine is running.

4. The combination as claimed in claim 3 in which said longitudenal slots intersect said exhaust ports;

whereby said slots act as crank case breathing passages.

5. The combination as claimed in claim 4 having an enlarged valve chamber, capable of storing gas under pressure.

6. The combination as claimed in claim 5 having a cylinder head mounted to said cylinder;

a gasket member positioned between said cylinder head and said cylinder; adapted to prevent fluid leakage from said cylinder.

7. The combination as claimed in claim 6 in which said valve guide is cylindrical;

8. The combination as claimed in claim 7 in which said constriction is positioned at the end portion of said valve guide opposite that of said valve seat.

lon- 

1. In an engine having a crank case with a crank rotably mounted therein, a cylinder, a partition member in said cylinder separating the interior of said cylinder into a valve chamber and a working chamber, means for delivering pressure fluid to said valve chamber, said partition member being provided with an opening therethrough having a valve seat, a valve member for engagement with said seat, a piston connected to said crank and reciprocable with a fixed stroke in said working chamber, said cylinder having exhaust ports at one and thereof controlled by the movement of said piston, an abutment carried by said piston movably into and through said opening to engage said valve and move it from its seat to admit pressure fluid to said working chamber for actuation said piston, and means for adjusting the extent of opening of said valve member comprising an adjustable connection between said cylinder and said crank case, the combination comprising: A valve guide integrally attached to said partition member and extending therefrom, said valve member positioned within said valve guide; said valve guide having a constriction therein, said constriction adapted to retain said valve member within said cylindrical valve guide.
 2. The combination as claimed in claim 1 in which said valve guide has a constriction therein, said constriction adapted to retain said valve member within said cylindrical valve guide.
 3. The combination as claimed in claim 1 in which said adjustable connection between said cylinder and said crank case is comprised of in combination: an expanded end portion of said cylinder, having longitudenal slots therein; an adjustable engagement between said expanded end portion and said crank case permitting longitudenal shift of said cylinder to vary the extent of opening of said valve; whereby said expanded portion of said cylinder bears against said crank case to create frictional rigidity allowing speed adjustment while said engine is running.
 4. The combination as claimed in claim 3 in which said longitudenal slots intersect said exhaust ports; whereby said slots act as crank case breathing passages.
 5. The combination as claimed in claim 4 having an enlarged valve chamber, capable of storing gas under pressure.
 6. The combination as claimed in claim 5 having a cylinder head mounted to said cylinder; a gasket member positioned between said cylinder head and said cylinder; adapted to prevent fluid leakage from said cylinder.
 7. The combination as claimed in claim 6 in which said valve guide is cylindrical;
 8. The combination as claimed in claim 7 in which said constriction is positioned at the end portion of said valve guide opposite that of said valve seat. 